Paris Observatory | 2018 Jan 09
[img3="The close environment of the red supergiant Betelgeuse (Credit: Pierre Kervella)The Betelgeuse star has a rotation period of about 30 years. With this discovery, published in Astronomy & Astrophysics on January 9, 2018, a scientific team under the direction of Pierre Kervella, astronomer at the Paris Observatory, opens new avenues to understand the mechanisms of loss of mass of this type of supergiant star.
The central image (orange colors) shows the surface of the star and the presence of a hot spot, while blue colors indicate the presence of dust created from the star’s ejected material."]https://www.obspm.fr/IMG/jpg/aori_conti ... omarks.jpg[/img3][hr][/hr]
Betelgeuse is one of the largest stars known. At a distance of 700 light-years, this is an evolved massive star. Its present radius reaches 1000 times that of the Sun, for a mass of about 15 times our star’s. Betelgeuse will end its existence with a supernova explosion, when its core will collapse. This spectacular event could happen within the next 10 000 to 100 000 years.
Thanks to observations obtained with the ALMA interferometer at sub-millimeter wavelengths, an international team lead by Pierre Kervella (Paris Observatory) observed the radio emission of two molecules present in the atmosphere of Betelgeuse: silicon monoxyde (SiO) and carbon monoxyde (CO). These two molecules are very abundant in the universe (including on Earth) and are also present in large quantities around the supergiant.
By measuring precisely the Doppler shift of the spectral lines emitted by the two molecules, the astronomers have observed that the north-west part of the star is coming toward us (blue shifted emission) at a velocity of 5 km/s and its south-east part is going away from us (red shifted emission) at the same speed. ...
The close circumstellar environment of Betelgeuse
V. Rotation velocity and molecular envelope properties from ALMA - Pierre Kervella et al
- Astronomy & Astrophysics 609:A67 (2018 Jan) DOI: 10.1051/0004-6361/201731761
arXiv.org > astro-ph > arXiv:1711.07983 > 21 Nov 2017 (v1), 28 Nov 2017 (v2)